Amplification of DNA sequences from chromosome 19q13.1 in human pancreatic cell lines

Conventional cytogenetics and comparative genomic hybridization (CGH) were utilized to identify recurrent chromosomal imbalances in 12 pancreatic adenocarcinoma cell lines. Multiple deletions and gains were observed in all cell lines. Losses affecting chromosomes or chromosome arms 9p, 13, 18q, 8p, 4, and 10p and gains involving chromosome arms or bands 19q13.1, 20q, 5p, 7p, 11q, 3q25-qter, 8q24, and 10q were commonly observed. Interestingly, 19 distinct sites of high-level amplification were found by CGH. Recurrent sites involved 19q13.1 (6 cases), 5p (3 cases), and 12p and 16p (2 cases). Amplification of KRAS2 was demonstrated in 2 cell lines and that of ERBB2 in another. To define the occurrence of chromosome 19 amplification further, two-dimensional analysis of NotI genomic restriction digests and fluorescence in situ hybridization using probes from band 19q13.1 were utilized. High-level amplification of overlapping sets of chromosome 19 NotI fragments was exhibited in 3 cell lines of which 2 showed amplification of both OZF and AKT2 genes and 1 that of AKT2 alone. In these 3 cell lines, amplification of chromosome 19 sequences was associated with the presence of a homogeneously staining region. Our results provide evidence of heterogeneity in the extent of chromosome 19 amplification and suggest the existence of yet unknown amplified genes that may play a role in pancreatic carcinogenesis.     

Spectral response of a point-contact diode in the submillimetre range

The spectral response of a fast GaAs point-contact diode in the millimetre- and submillimetre-wavelength range is described. N.E.P.s of 10-7W at 337 ?m and 4×10-6W at 98 ?m were obtained. The experimental and theoretical spectral responses for the diode are compared.     

On the internal dynamics of the Shanghai ranking

The Academic Ranking of World Universities (ARWU) published by researchers at Shanghai Jiao Tong University has become a major source of information for university administrators, country officials, students and the public at large. Recent discoveries regarding its internal dynamics allow the inversion of published ARWU indicator scores to reconstruct raw scores for 500 world class universities. This paper explores raw scores in the ARWU and in other contests to contrast the dynamics of rank-driven and score-driven tables, and to explain why the ARWU ranking is a score-driven procedure. We show that the ARWU indicators constitute sub-scales of a single factor accounting for research performance, and provide an account of the system of gains and non-linearities used by ARWU. The paper discusses the non-linearities selected by ARWU, concluding that they are designed to represent the regressive character of indicators measuring research performance. We propose that the utility and usability of the ARWU could be greatly improved by replacing the unwanted dynamical effects of the annual re-scaling based on raw scores of the best performers.     

Mechanism of electropolymerisation of methyl methacrylate and glycidyl acrylate on stainless steel

An aqueous based technique for producing uniform, thin, passive films of poly(methyl methacrylate) (PMMA) and poly(glycidyl acrylate) (PGA) on stainless steel electrodes has been developed. A cathodic free radical polymerisation mechanism is proposed based upon the results of cyclic voltammetry (CV), mechanistic electro-polymerisation and gel permeation chromatography (GPC) experiments. The polymerisation yield was increased by a synergistic relationship between sulphuric acid and potassium persulphate initiators, proposed to involve the formation of long-lived radical species. Termination reactions are believed to be inhibited by the formation of co-ordination complexes between the growing polymer chain and sulphuric acid. The mechanism accounts for the broad molecular weight distribution, cross-linking and post-electrolysis polymerisation, where polymer continued to form after the current flow ceased.     

A Light-Scattering System for High-Speed Cell Analysis

A flow-system instrument is described in which the light scattered by a biological cell is detected simultaneously at 32 angles in the forward direction as the cell passes through a focused laser beam at 10 m/s. Cluster analysis is applied to the scatter pattern data to enable discrimination among cell types.     

Facial injuries in hockey players

As otolaryngologists become more involved with maxillofacial trauma, we are encountering an increasing number of athletic injuries. Ice hockey accounts for a large number of these facial injuries. The fast moving and random nature of the game, frequent body and equipment contact and lack of protective devices, predisposes the hockey player to facial injury. Because of the roughly tenfold increase in hockey participation over the last decade, the problem of facial injury prevention has become a significant public health problem in North America. Review of the medical literature shows a paucity of interest in the subject of facial injury prevention in hockey. Several articles have dealt with ocular injury, while other articles have dealt with the general subject of hockey injury with only scant attention paid to the facial area. A retrospective study was carried out to more clearly define the scope of the facial injury problem. Four levels of hockey play were examined. Individuals from the youngest and most inexperienced to seasoned professionals were studied. An individually completed questionnaire was received from players in each group. It is the purpose of this paper to indicate the rates of injury for the various types of facial trauma, present their mechanisms of occurrence and discuss means of preventing facial injury in hockey players.